//
// reactive_deadline_timer_service.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2005 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#ifndef BOOST_ASIO_DETAIL_REACTIVE_DEADLINE_TIMER_SERVICE_HPP
#define BOOST_ASIO_DETAIL_REACTIVE_DEADLINE_TIMER_SERVICE_HPP

#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)

#include <boost/asio/detail/push_options.hpp>

#include <boost/asio/detail/push_options.hpp>
#include <cstddef>
#include <boost/config.hpp>
#include <boost/date_time/posix_time/posix_time_types.hpp>
#include <boost/asio/detail/pop_options.hpp>

#include <boost/asio/error.hpp>
#include <boost/asio/service_factory.hpp>
#include <boost/asio/detail/bind_handler.hpp>
#include <boost/asio/detail/noncopyable.hpp>
#include <boost/asio/detail/socket_ops.hpp>
#include <boost/asio/detail/socket_types.hpp>

namespace boost {
namespace asio {
namespace detail {

template <typename Demuxer, typename Time_Traits, typename Reactor>
class reactive_deadline_timer_service
{
public:
  // Implementation structure for a timer.
  struct timer_impl
    : private noncopyable
  {
    boost::posix_time::ptime expiry;
  };

  // The native type of the timer. This type is dependent on the underlying
  // implementation of the timer service.
  typedef timer_impl* impl_type;

  // The demuxer type for this service.
  typedef Demuxer demuxer_type;

  // The time type.
  typedef typename Time_Traits::time_type time_type;

  // The duration type.
  typedef typename Time_Traits::duration_type duration_type;

  // Constructor.
  reactive_deadline_timer_service(demuxer_type& d)
    : demuxer_(d),
      reactor_(d.get_service(service_factory<Reactor>()))
  {
  }

  // Get the demuxer associated with the service.
  demuxer_type& demuxer()
  {
    return demuxer_;
  }

  // Return a null timer implementation.
  static impl_type null()
  {
    return 0;
  }

  // Create a new timer implementation.
  void create(impl_type& impl)
  {
    impl = new timer_impl;
  }

  // Destroy a timer implementation.
  void destroy(impl_type& impl)
  {
    if (impl != null())
    {
      reactor_.cancel_timer(impl);
      delete impl;
      impl = null();
    }
  }

  // Get the expiry time for the timer as an absolute time.
  time_type expires_at(const impl_type& impl) const
  {
    return Time_Traits::from_utc(impl->expiry);
  }

  // Set the expiry time for the timer as an absolute time.
  void expires_at(impl_type& impl, const time_type& expiry_time)
  {
    impl->expiry = Time_Traits::to_utc(expiry_time);
  }

  // Get the expiry time for the timer relative to now.
  duration_type expires_from_now(const impl_type& impl) const
  {
    return Time_Traits::subtract(expires_at(impl), Time_Traits::now());
  }

  // Set the expiry time for the timer relative to now.
  void expires_from_now(impl_type& impl, const duration_type& expiry_time)
  {
    expires_at(impl, Time_Traits::add(Time_Traits::now(), expiry_time));
  }

  // Cancel any asynchronous wait operations associated with the timer.
  std::size_t cancel(impl_type& impl)
  {
    return reactor_.cancel_timer(impl);
  }

  // Perform a blocking wait on the timer.
  void wait(impl_type& impl)
  {
    boost::posix_time::ptime now
      = boost::posix_time::microsec_clock::universal_time();
    while (now < impl->expiry)
    {
      boost::posix_time::time_duration timeout = impl->expiry - now;
      ::timeval tv;
      tv.tv_sec = timeout.total_seconds();
      tv.tv_usec = timeout.total_microseconds() % 1000000;
      socket_ops::select(0, 0, 0, 0, &tv);
      now = boost::posix_time::microsec_clock::universal_time();
    }
  }

  template <typename Handler>
  class wait_handler
  {
  public:
    wait_handler(impl_type& impl, Demuxer& demuxer, Handler handler)
      : impl_(impl),
        demuxer_(demuxer),
        work_(demuxer),
        handler_(handler)
    {
    }

    void operator()(int result)
    {
      boost::asio::error e(result);
      demuxer_.post(detail::bind_handler(handler_, e));
    }

  private:
    impl_type& impl_;
    Demuxer& demuxer_;
    typename Demuxer::work work_;
    Handler handler_;
  };

  // Start an asynchronous wait on the timer.
  template <typename Handler>
  void async_wait(impl_type& impl, Handler handler)
  {
    reactor_.schedule_timer(impl->expiry,
        wait_handler<Handler>(impl, demuxer_, handler), impl);
  }

private:
  // The demuxer used for dispatching handlers.
  Demuxer& demuxer_;

  // The selector that performs event demultiplexing for the provider.
  Reactor& reactor_;
};

} // namespace detail
} // namespace asio
} // namespace boost

#include <boost/asio/detail/pop_options.hpp>

#endif // BOOST_ASIO_DETAIL_REACTIVE_DEADLINE_TIMER_SERVICE_HPP